Antibiotic Susceptibility and Minimum Inhibitory Concentration for Stenotrophomonas maltophilia Ocular Infections

Margaret Ming-Chih Ho; Ming-Hui Sun; Wei-Chi Wu; Chi-Chun Lai; Lung-Kun Yeh; Yih-Shiou Hwang; Ching-Hsi Hsiao; Kuan-Jen Chen

doi:10.3390/antibiotics11111457

Antibiotic Susceptibility and Minimum Inhibitory Concentration for Stenotrophomonas maltophilia Ocular Infections

Antibiotics (Basel). 2022 Oct 22;11(11):1457. doi: 10.3390/antibiotics11111457.

Authors

Margaret Ming-Chih Ho¹, Ming-Hui Sun^{1

2}, Wei-Chi Wu^{1

2}, Chi-Chun Lai^{2

3}, Lung-Kun Yeh^{1

2}, Yih-Shiou Hwang^{1

2}, Ching-Hsi Hsiao^{1

2}, Kuan-Jen Chen^{1

2}

Affiliations

¹ Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan.
² College of Medicine, Chang Gung University, Taoyuan 333, Taiwan.
³ Department of Ophthalmology, Chang Gung Memorial Hospital, Keelung 204, Taiwan.

Abstract

Stenotrophomonas maltophilia (S. maltophilia) is a Gram-negative, opportunistic pathogen that can lead to ocular infections, such as keratitis and endophthalmitis. The purpose of this study was to determine the antibiotic susceptibility and minimum inhibitory concentrations (MICs) of S. maltophilia isolates from ocular infections and to evaluate the differences in antibiotic MICs between keratitis and endophthalmitis isolates. The disc diffusion method revealed that S. maltophilia isolates exhibited 91% susceptibility to levofloxacin and moxifloxacin and 61% susceptibility to trimethoprim−sulfamethoxazole (TMP−SMX). The E-test indicated that S. maltophilia isolates exhibited 40%, 100%, 72%, 91%, 91%, and 93% susceptibility to ceftazidime, tigecycline, TMP−SMX, levofloxacin, gatifloxacin, and moxifloxacin, respectively. The MIC90 values of amikacin, ceftazidime, cefuroxime, tigecycline, TMP−SMX, levofloxacin, gatifloxacin, and moxifloxacin were >256, >256, >256, 3, >32, 1, 2, and 0.75 µg/mL, respectively. The geometric mean MICs of ceftazidime, TMP−SMX, levofloxacin, gatifloxacin, and moxifloxacin were significantly lower for the keratitis isolates than for the endophthalmitis isolates (p = 0.0047, 0.003, 0.0029, 0.0003, and 0.0004, respectively). Fluoroquinolones showed higher susceptibility and lower MICs for the S. maltophilia isolates when compared with other antibiotics. Fluoroquinolones can be recommended for treating S. maltophilia ocular infections. Tigecycline and TMP−SMX could be alternative antibiotics for S. maltophilia ocular infections.

Keywords: Stenotrophomonas maltophilia; antibiotic susceptibility; endophthalmitis; keratitis; minimum inhibitory concentration.

Grants and funding

This research was funded by a grant from the Taiwan Ministry of Science and Technology MOST 106-2314-B-182A-041 and Chang Gung Memorial Hospital CMRPG3 K1681.